Machine planning in a product model environment

The aim of this research was to understand and solve problems associated with the integration of a Machine Planner within a product model environment. This work was carried out in conjunction with other researchers, pursuing parallel integration issues related to pre-production proving and product data representation. Product data representations of component level planned, processes and feature level process data have been explored as sub-sets of -a product data model to aid integration. Geometric queries on a cell decomposition solid, model. have been explored as a means of providing feature geometric interaction data, while the dimensional interactions between features have also been addressed. Product data representations have been modelled using a prototype software tool, providing an environment for the exploration of the integration of a Machine Planner using a feature based design approach. Necessary Machine Planning functions have been implemented, using the ADA programming language, to explore the integrating capability of the product model environment, concentrating on the use of a prismatic benchmark component. Using the experimental implementation, setup and operation plans have been produced and machining part programs generated from product model representations of variants on the benchmark component. These have been successfully machined using a3 axis vertical machining centre. Such experiments, as well as others in conjunction with co-researchers, have shown that a product data model can provide a common base of data for the integration of a range of design and manufacturing activities

Host plant recognition by the root feeding clover weevil, Sitona lepidus (Coleoptera: Curculionidae)

This study investigated the ability of neonatal larvae of the root-feeding weevil, Sitona lepidus Gyllenhal, to locate white clover Trifolium repens L. (Fabaceae) roots growing in soil and to distinguish them from the roots of other species of clover and a co-occurring grass species. Choice experiments used a combination of invasive techniques and the novel technique of high resolution X-ray microtomography to non-invasively track larval movement in the soil towards plant roots. Burrowing distances towards roots of different plant species were also examined. Newly hatched S. lepidus recognized T. repens roots and moved preferentially towards them when given a choice of roots of subterranean clover, Trifolium subterraneum L. (Fabaceae), strawberry clover Trifolium fragiferum L. (Fabaceae), or perennial ryegrass Lolium perenneL. (Poaceae). Larvae recognized T. repens roots, whether released in groups of five or singly, when released 25 mm (meso-scale recognition) or 60 mm (macro-scale recognition) away from plant roots. There was no statistically significant difference in movement rates of larvae

Reference ontologies for interoperability across multiple assembly systems

The role of information and communication technologies (ICTs) is crucial for future manufacturing organisations in order to support effective collaboration and information sharing. However, the contemporary ICT-based systems lack the required ability to adequately support interoperability across multiple domain systems. The capability of such ICT-based systems to interoperate is impeded by the semantic conflicts arising from loosely defined meanings and intents of the participating system concepts. The aim of this paper is to investigate the interoperability of assembly systems at multiple levels of concept specialisations using the concept of a formal reference ontology. Formal ontologies are providing a promising way to computationally capture the domain meanings which can subsequently provide a base to support interoperability across multiple systems and in our case multiple assembly systems. This paper takes the example of manufacturing bill of materials concept and three different domain-specific interpretations to explore and demonstrate the potential of formal reference ontologies to support interoperability

Semantic reconciliation across design and manufacturing knowledge models: a logic-based approach

Ontology-based models of product design and manufacture are becoming increasingly important in the effort towards achieving interoperability among various stakeholders within and across product lifecycle systems. However, in the eventuality of having to interoperate between multiple ontology-based models, with the intention of sharing knowledge among them, the process still remains a difficult one. Although the concept of ontology mapping/matching has been developed as a means to interoperate across ontology-based models, yet the concept has remained relatively weak in terms of its ability to enable the formalization and verification of cross-model semantic correspondences in design and manufacture. In this paper, improved concepts to achieve semantic reconciliation are being investigated in the context of the Semantic Manufacturing Interoperability Framework (SMIF). The approach uses a Common Logic-based underpinning for enabling the evaluation and verification of cross-model correspondences. The approach has been successfully tested by applying the relevant logic-based mechanisms, in order to show the reconciliation of two individually developed knowledge models. Through this, it has been demonstrated that the approach enables semantic reconciliation of important structures within ontology-based models of design and manufacture. © 2011-IOS Press and the authors. All rights reserved

The configuration of design and manufacture knowledge models from a heavyweight ontological foundation

Problems related to knowledge sharing in design and manufacture, for supporting automated decision-making procedures, are associated with the inability to communicate the full meaning of concepts and their intent within and across system boundaries. To remedy these issues, it is important that the explicit structuring of semantics, i.e., meaning in computation form, is first performed and that these semantics become sharable across systems. This paper proposes an expressive (heavyweight) Common Logic-based ontological foundation as a basis for capturing the meaning of generic feature-oriented design and manufacture concepts. This ontological foundation serves as a semantic ground over which design and manufacture knowledge models can be configured in an integrity-driven way. The implications involved in the specification of the ontological foundation are discussed alongside the types of mechanisms that allow knowledge models to be configured. A test case scenario is then analysed in order to further support and verify the researched approach

An exploration of key information models and their relationships in global manufacturing decision support

Global manufacturing businesses are beginning to benefit from the information and knowledge support provided by modern IT tools such as Product Lifecycle Management (PLM), Enterprise Resource Planning (ERP), and Customer Relations Management (CRM). Many types of information and knowledge, from customer requirements through product information to global enterprise manufacturing capability are involved in global manufacturing decisions. Understanding the appropriate structures and relationships for this information and knowledge is a significant issue if effective wide-ranging support is to be provided. This paper focuses on global manufacturing decision support and explores three key types of information and knowledge relationship: (a) relationships between information and knowledge elements within a single information and knowledge model; (b) relationships between different information and knowledge models at one organizational level; (c) relationships between different information and knowledge models at different organizational levels. The corresponding information and knowledge structures have been presented with Unified Modelling Language (UML) to show the multiplicity of relationship required, and these are explored with an experimental system based on Rational Unified Process, Visual C++, and object-oriented DBMS ObjectStore. A case study has been pursued to explore the application of the information and knowledge models to a real industry environment

The reuse of machining knowledge to improve designer awareness through the configuration of knowledge libraries in PLM

The nature of competition induces the need to constantly improve and perform better. For global aerospace manufacturers, this is as timely an epithet as ever as market forces urge for more growth, better financial return and market position. The macroeconomic aspect is compounded by the growth of product complexity and the need for higher product quality, hence the drive to reduce waste places emphasis upon production costs and the need to improve product performance. This paper focuses upon a rapid development and deployment method that enables the capture and representation of machining knowledge so that it may be shared and reused by design engineers to accelerate the design-make process. The study and mapping of information and knowledge relationships are described and put forward as a lightweight ontology. From this, a set of knowledge document templates were created to facilitate the capture, structuring and sharing of machining knowledge within a collaborative multidisciplinary aerospace engineering environment. An experimental pilot system has been developed to test and demonstrate that knowledge document templates can accelerate the sharing of machining knowledge within an industrial product lifecycle management environment. The results are discussed to provide a case for further development and application within the product domain

Nematode movement along a chemical gradient in a structurally heterogeneous environment : 2. Theory

L'influence de l'hétérogénéité sur la diffusion chimique et le déplacement des nématodes est étudiée par le biais d'un modèle théorique. Ce modèle prend en compte trois facteurs influant sur le déplacement des nématodes : la structure du sol, la stratégie de recherche de nourriture et la chémotaxie. Utilisant un modèle continu, nous avons mis au point un système discret permettant de simuler les traces des nématodes dans chacune des quatre situations définies par Anderson et al. (1997). Nous avons montré que l'hétérogénéité structurale provoque aussi bien des taux variables de concentrations du composé attractif dans des aires réduites que la reconnaissance de ce composé. L'hétérogénéité structurale du sol limite également la stratégie de recherche de nourriture du nématode lequel adopte alors une stratégie permettant d'éviter les pièges structuraux. Il est démontré que des augmentations localisées de la densité structurale accroissent significativement la reconnaissance du composé attractif. (Résumé d'auteur

Methods for the capture of manufacture best practice in product lifecycle management

The capture of manufacturing best practice knowledge in product lifecycle management systems has significant potential to improve the quality of design decisions and minimise manufacturing problems during new product development. However, providing a reusable source of manufacturing best practice is difficult due to the complexity of the viewpoint relationships between products and the manufacturing processes and resources used to produce them. This paper discusses how best to organise manufacturing best practice knowledge, the relationships between elements of this knowledge plus their relationship to product information. The paper also explores the application of UML-2 as a system design tool which can model these relationships and hence support the reuse of system design models over time. The paper identifies a set of part family and feature libraries and, most significantly, the relationships between them, as a means of capturing best practice manufacturing knowledge and illustrates how these can be linked to manufacturing resource models and product information. Design for manufacture and machining best practice views are used in the paper to illustrate the concepts developed. An experimental knowledge based system has been developed and results generated using a power transmission shaft example

Product range models supporting design knowledge reuse

Redesign, where previous information is recovered in order to be adapted to a new situation, is an area of design where information technology can potentially provide substantial benefits. Information support to product design and manufacturing has been pursued through the use of product and manufacturing models. This paper introduces a new concept of a complementary information model, called a product range model, that aims to support variant and adaptive design activities. The general concept and structure of such an information model is defined in terms of product functions and their respective design solutions. The interactions taking place between particular design solution options are discussed, and methods are proposed for their evaluation against product specifications and design constraints. The concept of knowledge links is introduced to maintain the relationships between solutions within the product range model and the particular model of the product being developed. The work has been explored using injection mould tooling as an appropriate product range and evaluated through the design and implementation of a design support system utilizing an object-oriented database